First of all, the concept of express-session doesn't make sense outside of the HTTP request. It tells you what HTTP session a particular HTTP request belongs to. How do you want to know that without any HTTP request taking place? It doesn't make any sense.

Second, you are creating an Express application but you don't make it listen on any port so it is not really having any effect whatsoever.

Third, you set up a bunch of global variables inside of your TCP server handler which would conflict as soon as you have more than one request.

What you probably need here (though it's hard to guess from your question) is WebSocket. You can see my example of WebSocket client and server that I posted on GitHub: